The power dissipation of integrated circuit chips, and the modules containing the chips, continues to increase in order to achieve increases in processor performance. This trend poses a cooling challenge at both the module and system level. Increased air flow rates are needed to effectively cool high power modules and to limit the temperature of air that is exhausted into the computer center.
In many server applications, processors along with their associated electronics (e.g., memory, disc drives, power supplies, etc.) are packaged in removable drawer or blade configurations disposed within a housing. Typically, the components are cooled by air moving in parallel air flow paths, usually front-to-back, impelled by one or more air-moving devices (e.g., fans or blowers). In some cases, it may be possible to handle increased power dissipation within a single drawer or blade chassis by providing greater air flow, through the use of a more powerful air-moving device, or by increasing the rotational speed (i.e., RPMs) of an existing air-moving device. However, this approach is becoming problematic at the system level.
The sensible heat load carried by air exiting the electronics rack is stressing the ability of room air-conditioning to effectively handle the load. This is especially true for large installations with “server farms” or large banks of computer racks close together. In such installations, liquid cooling of selected components is an attractive technology to manage the higher heat fluxes. The liquid coolant absorbs the heat dissipated by selected components/modules in an efficient manner. Typically, the absorbed heat is ultimately transferred from the liquid to an outside environment, whether air or liquid-cooled.